This invention relates to transducers. More particularly, the invention relates to transducer assemblies which apply increased amounts of power to the earth around the transducer assemblies to obtain an enhanced recovery of oil from the earth.
As oil wells now in existence are being depleted, it has become increasingly difficult to discover new sources of oil and to recover the oil from these new sources. The oil being discovered is generally at increased depths under the earth""s surface. Furthermore, the oil is often viscous and is disposed at positions under the earth""s surface where it cannot be easily removed. For these and other reasons, it has become increasingly difficult to recover as much oil from the earth as would otherwise be desired.
Increased forces have had to be applied by the transducers to the earth around the transducers to separate the oil and recover the separated oil from the earth. The problems have been magnified because the characteristics of the earth, even at closely spaced positions, vary. These variable characteristics, even at closely spaced positions, prevent the transducers from operating efficiently to separate and recover the oil from positions below the earth""s surface.
A transducer member is made from a piezeoelectric material (e.g. lead zirconate titanate) having a looped configuration and a gap in the loop and having properties of vibrating upon the introduction of an electrical voltage to the transducer member. A support member made from steel or aluminum and having (a) a looped configuration and enveloping, and attached to, the transducer member has a gap aligned with the transducer member gap and has properties of vibrating with the transducer member.
The transducer member may have a uniform thickness around its periphery or a progressively increasing thickness with progressive distances from the gap. The transducer has a high mechanical Q (e.g. 8-12) and a particular resonant frequency when disposed in air or in a vacuum. When the transducer is disposed below the earth""s surface, its resonant frequency may vary because of variations in the earth""s characteristics at the different positions.
An alternating voltage having the particular frequency as its fundamental frequency is applied to the transducer member with a particular amplitude. The voltage has harmonics with large amplitudes (as in a square ware) relative to the particular amplitude. When the transducer member is disposed in the earth, sound pressure waves are produced in the transducer with larger amplitudes at harmonics and overtones of the fundamental frequency over a wider frequency range than the magnitude of the amplitude at the fundamental frequency. The harmonics and over tones produce an enhanced recovery of the oil from the earth regardless of the earth""s variable characteristics.